Fibrous (carboxyalkylthio)- and (carboxyarylthio) chlorodeoxycelluloses and method of preparation

ABSTRACT

THE PREPARATION OF CELLULOSIC YARNS AND FABRICS HAVING 0.6-11% OF THE CELLULOSIC HYDROXYL GROUPS REPLACED BY CHLORINE ATOMS, AND A FURTHER 0.3-9% OF THE HYDROXYL GROUPS REPLACED BY CARBOXYALKYLTHIO OR CARBOXYARYLTHIO GROUPS, IN ADDITION TO APPRECIABLE CELLULOSE CROSSLINKING, LEADS TO TEXTILES OF INCREASED WRINKLE RECOVERY IN THE WET STATE, INCREASED AFFINITY FOR MOISTURE AND METAL IONS, ENHANCED AFFINITY FOR BASIC DYES, AND INCREASED RESISTANCE TO CELLULOSE SOLVENTS. THE CELLULOSIC TEXTILE IS FIRST CONVERTED TO CHLORODEXYCELLOSE IN TEXTILE FROM BY REACTION WITH THIONYL CHLORIDE IN DIMETHYLFORMAMIDE AT 20-30* C., AND IS SUPSEQUENTLY REACTED WITH MERCAPTO-SUBSTITUTED CARBOXYLIC ACIDS AT TEMPERATURES OF 50-110*C., IN THE PRESENCE OF SUFFICENT ALKALI METAL HYDROXIDE TO CONVERT BOTH THE MERCAPTO- AND CARBOXYLIC ACID GROUPS TO THEIR ANIOMIC FORMS, IN A SOLVENT CONSISTING OF MIXTURES OF STRAIGHT CHAIN ALIPHATIC ALCOHOLS WITH WATER, TO REPLACE SOME OF THE CHLORINE ATOMS BY CARBOXYALKYLTHIO- OR CARBOXYARYLTHIO-GROUPS.

United States Patent ABSTRACT OF THE DISCLOSURE The preparation of cellulosic yarns and fabrics having 0.611% of the cellulosic hydroxyl groups replaced by 'chlorine atoms, and a further (LB-9% of the hydroxyl groups replaced by carboxyalkylthio or carboxyarylthio groups, in addition to appreciable cellulose crosslinking, leads to textiles of increased wrinkle recovery in the wet state, increased affinity for moisture and metal ions, enhanced afiinity for basic dyes, and increased resistance to cellulose solvents. The cellulosic textile is first converted to chlorodeoxycellulose in textile form by reaction with thionyl chloride in dimethylformamide at 2030 C., and is subsequently reacted with mercapto-substituted carboxylic acids at temperatures of 50110 C., in the presence of sufiicient alkali metal hydroxide to convert both the mercaptoand carboxylic acid groups to their anionic forms, in a solvent consisting of mixtures of straight chain aliphatic alcohols with water, to replace some of the chlorine atoms by carboxyalkylthioor carboxyarylthio-groups.

A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout the world for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to a method of introducing carboxyalkylthioor carboxyarylthio-substituents, together with chloro-substituents, into cellulosic molecules, as a means of preparing mixed derivatives of cellulose not hitherto described, but having novel properties and uses, particularly as textile materials and intermediates. More specifically, the present invention relates to the conversion of fibrous cellulose in the form of yarn and fabric to chlorodeoxycellulose, and subsequent replacement of a sizable fraction of the chlorine atoms therein by carboxya1kylthioor carboxyarylthio-groups. The introduction of these groups is accompanied by a low, controlled degree of cellulose crosslinking utilizing only a small fraction of the total number of the carboxyalkylthio or carboxyarylthio groups introduced, the resulting crosslinked (carboxyalkylthio)-chlorodeoxycelluloses or (carboxyarylthio)-chlorodeoxycelluloses retaining the fibrous form and yarn or fabric structure originally possessed by native, unmodified cellulose.

The types of cellulose to which the processes of this invention are applicable include native, mercerized, and regenerated celluloses derived from cotton and wood pulp. The cellulosic textile products prepared by the processes of this invention possess improved wrinkle re- 3,702,754 Patented Nov. 14, 1972 sistance, increased affinity for moisture and metal ions, improved dyeing properties, and enhanced resistance to attack by solvents for native celluloses,

The main object of the present invention is to provide chemically substituted fibrous celluloses, wherein each cellulose molecule contains two kinds of chemical substituents, specifically, chloro substituents, on the one hand, and carboxyalkylthio or carboxyarylthio groups, on the other hand. By virtue of replacement of some of the hydroxyl groups of the cellulose by these substituents, the resulting fibrous mixed derivatives of cellulose have enhanced utility as textile materials, and as intermediates for further chemical modification leading to various other textile materials.

A second object of the present invention is to provide a means of introducing a limited degree of cellulose crosslinking in cellulosic textiles, so as to impart increased wrinkle resistance in the wet state, and increased resistance to cellulose solvents, without causing significant losses in tensile strength during the crosslinking step.

A third object of the present invention is to provide a means of rendering cellulosic textiles receptive to basic dyes which lack substantivity for native cellulose.

A fourth object of the present invention is to provide a means of imparting cationic-exchange capacity and metal ion-sequestering properties, as well as anionic properties to cellulosic textiles, such properties being useful in attaching ionic fungicides, :rotproofing agents, and other ionic finishing agents to said textiles.

The fifth object of the present invention is to provide increased moisture absorption to cellulosic textiles, such property being useful in improving the comfort factor of said textiles. Other objects will become apparent in the description of the invention.

The (carboxyalkylthio)- and (carboxyarylthio)-chlorodeoxycelluloses of the present invention are formed by the reaction of certain aliphatic and aromatic mercaptosubstituted carboxylic acids with fibrous chlorodeoxycellulose, the latter being preferably in yarn or fabric form. To prepare the chlorodeoxycellulose yarns and fabrics required in the present processes, the known reaction of thionyl chloride with cellulose may be used. This reaction has hitherto been run only on dispersed cellulose fibers. As the reaction medium, dimethylformamide is advantageous inasmuch as it suppresses cellulose degradation by effectively complexing with free hydrochloric acid, as previously shown by Polyakov and Rogovin, Vysokomol. Soedin. 5, (1) 11-17 (1963); Chem. Abstr. 59, 660411 (1963); whereas other reaction media such as pyridine cause extensive yellowing and degradation of the cellulose. Although these workers recommended reaction temperatures of -98 C. in treating cotton linters with thionyl chloride in dimethylformamide, they noted yellowing in the cotton so treated. In the present treatments carried out on cellulosic yarns, and fabrics, it is found that such elevated temperatures cause severe tendering as well as yellowing. The preparation of chlorodeoxycellulose yarns and fabrics for use in the process of the present invention require the use of lower reaction temperatures, in the range of 20-30 C., thereby avoiding yellowing and tendering of the cellulose.

Reaction times of 05-24 hours may be employed in preparing the chlorodeoxycellulose, depending on chlorine content desired. Although the reaction with thionyl chloride may be carried out on native cellulose, the reaction is much more rapid and complete when conducted on wet-swollen cellulose, obtained by treatment with mercerizing alkali such as 16-30% aqueous sodium hydroxide, the aqueous alkali being removed by washing and solvent-exchanged prior to treatment of the cellulose with thionyl chloride in dimethylformamide. This washing and solvent-exchange can be done by first washing the cellulose fiber, yarn, or fabric with water to remove alkali, then washing with a water-miscible, cellulose-inert solvent such as ethanol to remove water, and finally with an inert aprotic solvent such as benzene to remove the ethanol. Reaction of thionyl chloride with the solventexchanged cellulose in dimethylformamide may then be carried out either by adding the thionyl chloride to the suspension of cellulose in dimethylformamide, or by adding the cellulose to a solution of thionyl chloride in dimethylformamide. The chlorodeoxycellulose so produced may be washed with ice water or dimethylformamide, then ice water, to remove excess thionyl chloride, and then with 14% aqueous ammonium hydroxide at room temperature to remove sulfur-containing byproducts. The yarn or fabric may then be washed with water, then acetone, and dried. The concentration of thionyl chloride in the liquid phase of the reaction mixture, during the conversion of the cellulose to chlorodeoxycellulose, is preferably kept in the range of 220% by weight. Lower thionyl chloride concentrations give very slow reaction, while higher concentrations than these tend to induce cellulose degradation.

Chlorodeoxycellulose produced in this manner, and suitable for use in carrying out the processes of the present invention, contains 0.6-7.5 chlorine. The exact chlorine content obtained depends on the reaction time, temperature, thionyl chloride concentration, and whether the cellulose was mercerized and solvent-exchanged prior to treatment. In the resulting chlorodeoxycellulose, the numerical ratio of chlorine atoms to anhydroglucose units in the cellulose chains is preferably in the range of 0.03- 0.35.

The conversion of cellulose to chlorodeoxycellulose may be represented by the equation:

CelluloSe-OH+SOCl Cellulose-Cl-|SO +HCl In the presence of alkali metal hydroxide, such as potassium hydroxide, the resulting chlorodeoxycellulose has the capability of reacting with an excess of an alkyl or aryl thiol, RSH, at elevated temperatures as follows:

RSH+KOH RSK+H O Cellulose-Cl+RSK Cellulose-SR+ KCl Alkylthioethers of cellulose have previously been prepared by Clingman and Schwenker, J. Poly. Sci., Pt. C [11] 107-118 (1965) by reacting cellulose tosylate with aliphatic monomercapto and dimercapto compounds. Moderate wet and dry wrinkle recovery was obtained by these Workers, but only when using difunctional aliphatic thiols which would be expected to lead to crosslinking of the cellulose. Moreover, the tensile strength losses were in the order of 40 to 70% after reaction. Also, these particular thiols were quite offensive in odor and difiicult to remove from the cellulose fiber. When applying monothiols, Clingman and Schwenker obtained no cellulose crosslinking and no appreciable increase in wrinkle resistance.

The compounds, which, however, are found to be suitable for reaction with chlorodeoxycellulose in the processes of the present invention are mercapto carboxylic acids having the structure HSQ-COOH, where Q is a divalent organic radical selected from the group consisting of (a) alkylene radicals having the structure where n is an integer from 1 to 4 inclusive, (b) carboxyalkylene radicals having the structure where n is as already defined, and (c) phenylene radicals having the structure -C H which may be ortho, meta or para. Under the conditions of the present process, reaction of the mercapto carboxylic acid with the chlorodeoxycellulose results in displacement of up to of the chlorine atoms in the latter by carboxyalkylthio or carboxyarylthio groups having the structure which are formed in the cellulose is in most instances too small to be detected analytically, although the occurrence of these crosslinks is readily detected by the insolubility of the product in cellulose solvents such as 0.5 molar aqueous cupriethylenediamine. That the degree of cellulose crosslinking is small is borne out by the considerable swelling and in certain instances partial dissolution that such cellulose solvents induce in the fibers of the product. In order for the product to have the desired properties, the numerical ratio of carboxyalkylthio or carboxyarylthio groups/anhydroglucose units in the product must be in the range of 0.01 to 0.26.

The fibrous, water-insoluble (carboxyalkylthio)- and (carboxyarylthio)-chlorodeoxycelluloses formed as the product of the present processes have the structure where Z represents a segment of a crosslinked cellulose chain which segment contains anhydroglucose units, m has values in the range of 3 to 35, b has values in the range of 1 to 26 but does not exceed 0.8 m, and Q represents a divalent organic radical selected from the group consisting of (a) alkylene radicals having the structure C H where n is an integer from 1 to 4 inclusive, (b) carboxyalkylene radicals having the structure where n is as already defined, and (c) phenylene radicals having the structure C H which may be ortho, meta or para, the aforesaid crosslinks in Z having the structure the number of these crosslinks being sufiicient to impart at least partial insolubility of the fibrous product in cellulose solvents such as aqueous 0.5 molar cupriethylenediamine, but insufficient to prevent swelling of the fibrous product in said cellulose solvents. As is evident in this structure, the number of chlorine atoms per 100 anhydroglucose units is given by (m-b) which has values in the range of 2 to 34.

As already indicated, the introduction of -a certain class of carboxyalkylthio or carboxyarylthio substituents into chlorodeoxycellulose is necessary to impart textile properties characteristic of the products of the present invention. The presence of the carboxylic acid groups is necessary for the products to have the ability to pick up metal ions, or to have increased moisture content. The use of monothiols is essential, for as previously shown in J. Poly. Sci. Pt. C [11] 107-118 (1965), the reaction of dithiols imparts crease recovery at the expense of considerable strength loss in the cellulose, and simple monofunctional thiols not containing carboxyl groups are inelfective in improving either the wet or dry crease recovery of the cellulose. Thus the wrinkle recovery imparted by processes of the present invention is unexpected.

The process of the present invention, whereby fibrous, shortly crosslin-ked (carboxyalkylthio)- and (carboxyary1- thio)-chlorodeoxycelluloses in textile form are obtained, comprises the following steps:

(a) conversion of fibrous cellulose in textile form to fibrous chlorodeoxycellulose in textile form, the ratio of chlorine atoms to anhydroglucose units in said chlorodeoxycellulose being about from 0.03 to 0.35,

(b) immersing the chlorodeoxycellulose textile in a solution of a mercapto carboxylic acid in a mixture of water and a straight-chain aliphatic alcohol having from 1 to 4 carbon atoms, the proportion of water in the mixture of water and aliphatic alcohol being from about 20% to 80% by weight, the said solution of mercapto .carboxylic acid having been neutralized with one equivalent of an alkali metal hydroxide for each equivalent of mercapto and carboxyl groups in the mercapto carboxylic acid, the said mercapto carboxylic acid having the structure HS-Q-COOH where Q is a divalent organic radical selected from the group consisting of (a) alkylene radicals having the structure C H wherein n is an integer from 1 to 4 inclusive, (b) carboxyalkylene radicals having the structure -C H (COO'H)- where n is as already defined, and (c) phenylene radicals having the structure -C H which may be ortho, meta or para, the concentration of the mercapto carboxylic acid in the solution being about from 3% to 20% by weight, the temperature of said solution being about from 50 C. to 110 C. and the duration of said immersion being about from 0.5 to 2.5 hours,

(c) washing the textile to remove excess mercapto acid and alkali metal hydroxide, and

(d) drying the textile.

Typical examples of mercapto-substituted carboxylic acids suitable for reaction with chlorodeoxycellulose by the above process are the following:

thioglycolic acid 3-mercaptopropionic acid 4-mercaptobutyric acid Z-mercaptosuccinic acid o-mercaptobenzoic acid The desired introduction of carboxyalkylthioor carboxyarylthio-group is most efiicient and rapid with mercaptocarboxylic acids having low molecular weight. The process becomes slow and incomplete, and base-catalyzed hydrolysis of chlorodeoxycellulose as well as dehydrochlorination, becomes an important side reaction, when mercapto carboxylic acids of high molecular weight are utilized. These side reactions are evidenced by a lower than predicted ratio of sulfur atoms introduced/chlorine atoms displaced, during the mercapto carboxylic acid treatment.

In carrying out step (b) of the above process, it is highly desirable to have a diluent or diluents present in order to control the degree of cellulose crosslinking obtained, and to suppress side reactions such as hydrolysis and dehydrochlorination. The diluent or mixture of diluents should have a boiling point at least as high as the desired temperature at which the reaction of step (b) is to be conducted. The diluents should be highly polar as Well as highly hydrogen bonded, since the desired displacement of chlorine in chlorodeoxycellulose by carboxyalkylthioand carboxyarylthio-groups proceeds through ionic intermediates, and the formation of such intermediate is far more rapid in solvents of high polarity and high hydrogen-bonding capacity, than in nonpolar, aprotic solvents. The molecular weight of the diluents should be as low as is consistent with these requirements, since highmolecular-weight diluents do not penetrate cellulose readily.

Also, the diluents should render the mercapto carboxylic acids soluble, and should be chemically inert to the mercapto acids and to the chlorodeoxycellulose, as well as being readily miscible in water, so that the diluents can be removed by washing of the textile material. Among the diluents which meet these requirements are mixtures of water with the lower straight chain aliphatic alcohols such as methanol, ethanol, 1-propanol, and l-butanol.

Reaction temperatures suitable in step (b) of the above process are in the range of 50-ll0 C., with temperatures of 60l00 C. being preferred. At low temperatures, below those listed, the reaction becomes slow and incomplete, while at excessively high temperatures, uncontrolled crosslinking yellowing, hydrolysis, and dehydrochlorination of the chlorodeoxycellulose tend to occur, with accompanying tendering and degradation of the textile material. At the preferred temperatures, mixtures of ethanol and water are the diluents of choice from the standpoint of economy and elfectiveness.

As already indicated, the reaction of aliphatic or aromatic mercapto carboxylic acids with the chlorodeoxycellulose in step ('b) of the above process, results in replacement of 20-80% of the chlorine atoms in chlorodeoxycellulose by carboxyalkylthioor carboxyarylthiogroups. The ratio of sulfur-containing substituents to chlorine in the final product can be adjusted over a wide range by the proper choice of reaction time used in step (b), the reaction commencing when the chlorodeoxycellulose textile is immersed in the heated alkaline solution of mercapto carboxylic acid, and ceasing when the textile is removed from this heated solution.

The washing step (c) in the above process can be carried out by boiling with an inert, water-miscible solvent, followed by washing at ambient temperature with water. Suitable water-miscible organic solvents which facilitate removal of unreacted mercapto acids occluded in the interior of the treated fibers are loW molecular- Weight alcohols such as methanol and ethanol.

The drying step (d) may be conducted at any convenient temperature that does not cause excessive yellowing or air-oxidation of the (carboxyalkylthio)- and (carboxyarylthio)-chlorodeoxycelluloses. Drying temperatures in the range of 20-ll0 C. are preferred.

In the examples that follow, all parts and percentages are by weight. Wrinkle recovery of the treated fabrics was determined with the Monsanto tester.

EXAMPLE 1 Preparation of chlorodeoxycellulose yarn Kiered, 12/3 cotton yarn was immersed in 23% aqueous sodium hydroxide for one hour at 25 C., Washed with excess tap water, then washed with distilled water until the washings were neutral to phenolphthalein indicator. The yarn was next immersed in aqueous ethanol for 24 hours. The yarn was then rinsed several times with benzene, and allowed to soak in benzene for 24 hours. The yarn was then squeezed to free it of excess benzene, and immersed in 32 times its own weight of dirnethylformamide. While the yarn was immersed in the dimethylformamide, thionyl chloride was added dropwise to the latter, at such a rate as to keep the temperature of the mixture below 30 C., the addition being continued until 8.0 parts by weight of thionyl chloride had been added for each part by weight of cotton cellulose yarn. The addition required approximately one hour. The reaction mixture was then shaken in a stoppered container for 4 hours at 25 C. The yarn was then removed from the liquid, washed with ice water until the washings showed a pH of 4 or greater, and was then washed with water at room temperature. The yarn was subsequently immersed in 3% aqueous ammonium hydroxide for one hour, washed with water, then acetone, and was air-dried to yield fibrous chlorodeoxycellulose yarn having a chlorine content of 4.6% (dry basis), and a moisture content of 1 0.5%. Fibers of the treated yarn were soluble in 0.5 molar aqueous cupriethylenediamine, showing that the chlorodeoxycellulose was not crosslinked.

The breaking strength of the chlorodeoxycellulose yarn was 4.3 lbs., as compared to 5.2-5.5 lbs. for the original, untreated yarn. The elongation-at-break was 24.9% for treated yarn as compared to 12.1% prior to treatment. Tenacity of treated yarn was 9.6 g./tex as compared to 17.5 g./tex for untreated yarn. Energy-ta rupture was 3.0 in.-lbs. for treated yarn, as compared to 2.3 in.-lbs. for untreated yarn.

The chlorodeoxycellulose yarn was only faintly colored by basic dyes such as methylene blue, indicating a lack of affinity for such dyes. The chlorodeoxycellulose yarn was ineffective in picking up metal ions from aqueous solution. For example, immersion of the treated yarn for an hr. at 25 C. in 2% aqueous solution of cupric sulfate pntahydrateQor in 2% aqueous solution of lead (II) acetate trihydrate, followed by subsequent washing in water for 30 mins.,and air-drying, fixed only 0.01% copper or 0.18% lead in the treated yarn.

EXAMPLE 2 Reaction of chlorodeoxycellulose yarn with thioglycolic acid A sample of the chlorodeoxycellulose yarn prepared by the procedure in Example 1 was immersed at 60 C. for 1 hr. in forty times its own weight of 4.5% thioglycolic acid, 5.5% potassium hydroxide, 45% ethanol, and 45% Water. Subsequently, the yarn was boiled in 95% ethanol for 30 minutes, to remove most of the excess thioglycolic acid, and was then washed in tap water for 30 minutes, to remove alkali and alcohol from the chemically modified cellulose. The yarn was then airdried to give a partially substituted (carboxymethylthio)- chlorodeoxycellulose yarn having a sulfur content of 1.4% and a chlorine content of 2.7%. The ash content was 2.3%, and the moisture content 12.2%, the latter being significantly higher than the 10.5% moisture content observed for chlorodeoxycellulose yarn in Example 1. The resultant yarn possessed a low but appreciable degree of cellulose crosslinking inasmuch as fibers of the yarn were partially insoluble in 0.5 molar cupriethylenediamine. The yarn was dyed a medium blue shade by an aqueous solution of the basic dye methylene blue.

The breaking strength of the (carboxymethylthio)- chlorodeoxycellulose yarn Was,5.0 lbs., compared to 4.3 lbs. for the chlorodeoxycellulose yarn. Elongation-atbreak was 28.1% for the treated yarn as compared to 24.9% for the chlorodeoxycellulose yarn. The tenacity remained essentially unchanged, being 9.9 g./tex for the treated yarn, and 9.6 g./tex for the chlorodeoxycellulose yarn. The energy-to-rupture increased markedly, going from 3.0 in.-lbs. for the chlorodeoxycellulose yarn to 4.4 in.-lbs. for the carboxymethylthiodeoxycellulose yarn.

Thioglycolic acid was also reacted under the same conditions described earlier in this example, at 100 C. with the chlorodeoxycellulose yarn in Example 1, to give a-partially substituted (carboxymethylthio)-chlorodeoxycellulose yarn having a sulfur content of 2.7% and a chlorine content of 1.1%. The ash content was 1.3% and the moisture content 12.4%, the latter being again significantly higher than the moisture content of chlorode oxycellulose yarn (10.5 Fibers of the resultant yarn were partly insoluble in 0.5 molar cupriethylenediamine. The yarn was dyed a medium blue shade with the basic dye methylene blue.

The breaking strength of the resultant yarn was 3.8 lbs., the elongation-'at-break had a value of 38.4%, tenacity was 6.9 g./tex, and the energy-to-rupture had a value of 3.9 in.-lbs.

This (carboxymethylthio)-chlorodeoxycellulose yarn, when immersed for one hour at 25 C. in 2% aqueous cupric sulfate pentahydrate, then washed with tap water for 30 minutes, and air-dried, resulted'in a yarn containing 0.92% copper. Similarly, when a sample of the (carboxymethylthio)-chlorodeoxycellulose yarn was immersed in 2% aqueous lead (II) acetate trihydrate for one hour at 25 C., and then washed and dried, the resulting yarn was found to contain 1.68% lead durably fixed in the yarn.

EXAMPLE 3 Reaction of chlorodeoxycellulose yarn with 3- mercaptopropionic acid A sample of the chlorodeoxycellulose yarn prepared as described in Example 1, was immersed at 60 C. for an hour in forty times its own weight of a solution containing 5.3% 3-mercaptopropionic acid, 5.5% potassium hydroxide, 44.6% ethanol, and 44.6% water. The yarn was then boiled in ethanol for 30 minutes, and was washed in tap water for 30 minutes. The yarn was afterwards air-dried to give partially substituted (2-carboxy ethylthio)-chlorodeoxycellulose yarn having a sulfur content of 2.9% and a chlorine content of 1.8%. The ash content was 4.1%, and the moisture content 11.5%, the latter being appreciably greater than that observed with chlorodeoxycellulose yarn. Fibers of the resultant yarn were partly insoluble in 0.5 molar cupriethylenediamine, indicating they possessed a low but appreciable degree of cellulose crosslinking. The yarn was dyed a blue shade with the basic dye methylene blue.

The breaking strength of the (2-carboxyethylthio)- chlorodeoxycellulose yarn was 4.6 lbs., its elongation-atbreak had a value of 28.0%, tenacity was 8.6 g./tex and the energy-to-rupture was 4.3 in.-lbs.

EXAMPLE 4 Reaction of chlorodeoxycellulose yarn with 4- mercaptobutyric acid A sample of the chlorodeoxycellulose yarn prepared as described in Example 1, was immersed at 60 C. for .an hour in forty times its own weight of solution containing 6.0% 4-mercaptobutyric acid, 5.6% potassium hydroxide, 44.2% ethanol, and 44.2% water. The yarn was then boiled in 95 ethanol for 30 minutes, and was washed in tap water for 30 minutes. The yarn was afterwards airdried, to give partly substituted (3-carboxypropylthio)- chlorodeoxycellulose yarn having a sulfur content of 1.6% and a chlorine content of 3.7%. The ash content was 2.4% and the moisturecontent 10.9%, or somewhat higher than that observed with chlorodeoxycellulose yarn. The resultant yarn was only swollen and partially dissolved by 0.5 molar cupriethylenediamine, and dyed a medium blue shade with the basic dye methylene blue.

,The breaking strength of the resultant ,(B-CaIbOKYPI'OPyI- thio)- chlorodeoxycellulose was 5.5 lbs., with an elongation-at-break of 32.4%; it had atenacity of 10.7 g./tex and an energy-to-rupture value of 5.0 in.-lbs..

EXAMPLE 5 Reaction of chlorodeoxycellulose yarn with o-mercaptobenzoic acid A sample of the chlorodeoxycellulose yarn prepared as described in Example 1 was immersed at C. for an hour in forty times its own weight of a solution containing 7.7% o-mercaptobenzoic acid, 5.5% potassium hydroxide, 43.4% ethanol, and 43.4% water. The yarn was then boiled in '95 ethanol for 30 minutes, and was washed in tap water for 30 minutes. The yarn was afterwards airdried to give partially substituted (o-carboxyphenylthio)- chlorodeoxycellulose yarn havinga sulfur content of 2.5% and a chlorine content of 1.1%. Fibers of the resultant yarn were only swollen and partly dissolved by 0.5 M cupriethylenediamine. The yarn was dyed a light blue shade with the basic dye methylene blue.

The breaking strength of the resultant (o-carboxyphenylthio)-chlorodeoxycellulose yarn was 5.5 lbs., with an elongation-at-break of 31.8% a tenacity of 10.0 g./tex, and an energy-to-rupture of 4.9 in.-lbs.

EXAMPLE 6 Reaction of chlorodeoxycellulose yarn with Z-mercaptosuccinic acid A sample of the chlorodeoxycellulose yarn prepared as described in Example 1 was immersed at 60 C. for an hour in forty times its own weight of solution containing 7.5% Z-mercaptosuccinic acid, 8.5% potassium hydroxide, 50.5% water, and 33.5% ethanol. The yarn was then boiled in 95% ethanol for 30 minutes, and was washed in tap water for 30 minutes. The yarn was afterwards airdried, to give a partly substituted (l,2-dicarboxyethylthio)- chlorodeoxycellulose yarn having a sulfur content of 1.3% and a chlorine content of 2.8%. The ash content was 3.7%, and the moisture content 11.9%, significantly higher than that observed in chlorodeoxycellulose yarns. The resultant yarn was dyed a medium blue shade with the basic dye methylene blue, and was only partly dissolved by the cellulose solvent 0.5 M cupriethylenediamine.

The resultant yarn possessed a breaking strength of 4.7 lbs., an elongation-at-break of 40.7%, a tenacity of 7.9 g./tex, and an energy-to-rupture value of 4.9 in.-lbs.

The above (1,2-dicarboxyethylthio)-chlorodeoxycellulose yarn, when immersed for one hour at 25 C., in 2% aqueous cupric sulfate pentahydrate, followed by subsequent washing for 30 minutes in tap water, and then airdrying, contained 0.97% copper. Similarly, when the sample of the (1,2-dicarboxyethylthio)-chlorodeoxycellulose yarn was immersed in 2% aqueous lead (11) acetate trihydrate for one hour at 25 C., and then washed and dried, the yarn was found to contain 1.46% lead.

EXAMPLE 7 Preparation of chlorodeoxycellulose fabric Cotton 80 x 80 print cloth, which had previously been desized, scoured, and bleached, was immersed in 23% aqueous sodium hydroxide at constant dimensions for 30 minutes at 25 C. Subsequently the cloth was washed with excess tap water, and then with distilled water until the washings were neutral to phenolphthalein indicator. The fabric was then rinsed several times in 95% aqueous ethanol, rinsed several times with benzene, then allowed to soak in benzene for 43 hours. The fabric was then immersed in dimethylformamide several times to remove the benzene, and was then allowed to react at 25 C. for 21 hours with a solution containing 32 parts by weight of dimethylformamide and 8 parts by weight of thionyl chloride per part by weight of cotton fabric. The fabric was then removed from the liquid, washed with dimethylformamide, and then washed with ice water until the washings were weakly acidic, as indicated by a pH of 4 or greater. Finally, the cloth was washed with water at ambient temperature. The fabric was subsequently immersed in 3% aqueous ammonium hydroxide for an hour, washed with water, rinsed in acetone, and oven-dried at 80-90" C., to yield fibrous chlorodeoxycellulose fabric having a chlorine content of 5.9%. The fibers of the chlorodeoxycellulose fabric exhibited the same behavior towards cellulose solvents as did fibers of the chlorodeoxycellulose yarn in Example 1; that is, they readily dissolved in 0.5 molar aqueous cupriethylenediamine, indicating the absence of cellulose crosslinking in these fibers.

The chlorodeoxycellulose fabric was only lightly colored by basic dyes such as methylene blue, and was ineffective in picking up metal ions such as copper from aqueous solutions; on immersion for an hour at 25 C. in

a 2% aqueous solution of cupric sulfate pentahydrate, followed by subsequent washing with tap water, and airdrying, it contained only 0.01% .Cu.

10 EXAMPLE 8 Reaction of chlorodeoxycellulose fabric with o-mercaptobenzoic acid A sample of the chlorodeoxycellulose fabric prepared as described in Example 7 was immersed at 60 C. for an hour in twenty-five times its own weight of a solution containing 12% o-mercaptobenzoic acid, 9% potassium hydroxide, 39.5% ethanol, and 39.5% water. The fabric was then boiled in 95 ethanol for 30 minutes, and was washed in tap water for 60 minutes. The fabric was afterwards dried for 10 minutes at 85 C. to yield partially substituted (o-carboxyphenylthio) chlorodeoxycellulose fabric containing 1.9% sulfur and 1.3% chlorine. The resultant fabric dyed a deep blue shade with the basic dye methylene blue. Fibers of this fabric were swollen but only partially dissolved by the cellulose solvent 0.5 molar aqueous cupriethylenediamine, showing that a low level of crosslinking had occurred in the fabric during treatment.

The wet wrinkle recovery (warp-l-fill) of the resultant fabric was considerably improved over that of the chlorodeoxycellulose fabric, the latter fabric having a value of only 187', while the former possessed a value of 233. Similarly, the ability to absorb metal ions from solution was improved, since the (o-carboxyphenylthio)-chlorodeoxycellulose fabric had a copper content of 0.80% after being immersed in 2% aqueous cupric sulfate pentahydrate for an hour at 25 C., even after subsequent washing with water for 30 minutes and air-drying, as opposed to only 0.01% copper in the chlorodeoxycellulose fabric.

We claim:

1. A process for preparing a fibrous, crosslinked chlorodeoxycellulose derivative, in textile form, and selected from the group consisting of (carboxyalkylthio)- chlorodeoxycelluloses and (carboxyarylthio)-chlorodeoxycelluloses, comprising:

(a) impregnating a fibrous cellulose textile with an aqueous 16% to 30% sodium hydroxide solution to obtain a swollen fiber structure,

(b) removing the sodium hydroxide by water-washing and solvent-exchanging with a water-miscible, cellulose-inert solvent, followed by exchanging with an inert aprotic solvent,

(c) reacting the resulting swollen fibrous cellulose with 2% to 20% thionyl chloride in dimethylformamide solution, for about from 30 minutes to 24 hours, at a temperature of about from 20 C. to 30 C.,

((1) Washing the reacted fibrous cellulose with dimethylformamide, ice water, and an aqueous 1% to 4% ammonia solution at room temperature to remove sulfur-containing byproducts and obtain a fibrous chlorodeoxycellulose in textile form containing about from 0.6% to 7.5% chlorine,

(e) immersing and reacting the immersed chlorodeoxycellulose textile in a solution of a mercapto carboxylic acid in a mixture of water and a straight-chain aliphatic alcohol having from 1 to 4 carbon atoms, the proportion of water in the mixture of water and aliphatic alcohol being from about 20% to 80% by weight, the said solution of mercapto carboxylic acid having been neutralized with one equivalent of an alkali metal hydroxide for each equivalent of mercapto and carboxyl groups in the mercapto carboxylic acid, the said mercapto carboxylic acid having the structure HS-Q-OOOH where Q is a divalent organic radical selected from the group consisting of (1) an alkylene radical having the structure C H where n is an integer from 1 to 4 inclusive, (2) a carboxyalkylene radical having the structure -C I-I (COOH)-- where n is as already defined, and (3) a phenylene radical having the structure C H the concentration of the mercapto carboxylic acid in the solution being from 3% to 20% by weight, the temperature of said solution being about from 50 C. to 110 C. and the duration of said immersion being about from 0.5 to 2.5 hours,

(f) washing the thus-reacted textile to remove excess mercapto carboxylic acid and alkali metal hydroxide, and

(g) drying the washed textile.

2. The process of claim 1 wherein the textile is in the form of a yarn.

3. The process of claim 1 wherein the textile is in the form of a fabric.

4. The process of claim 1 wherein the water-miscible, cellulose-inert solvent is ethanol.

5. The process of claim 1 wherein the aprotic solvent is benzene.

6. A process for preparing a fibrous, crosslinked (carboxyal'kylthio)-chlorodeoxycellulose in textile form, comprising:

(a) impregnating a fibrous cellulose textile with an aqueous 16% to 30% sodium hydroxide solution to obtain a swollen fiber structure,

(b) removing the sodium hydroxide by water-washing and solvent-exchanging with a water-miscible, cellulose-inert solvent, followed by exchanging with an inert aprotic solvent,

(c) reacting the resulting swollen fibrous cellulose with 2% to thionyl chloride in dimethylformamide solution, for about from minutes to 24 hours, at a temperature of about from 20 C. to 30 C.,

(d) washing the reacted fibrous cellulose with dimethylformamide, ice water, and an aqueous 1% to 4% ammonia solution at room temperature to remove sulfur-containing byproducts and obtain a fibrous chlorodeoxycellulose in textile form containing about from 0.6% to 7.5% chlorine,

(e) immersing and reacting the immersed chlorodeoxycellulose textile in a solution of a mercapto carboxylic acid in a mixture of water and a straightchain aliphatic alcohol having from 1 to 4 carbon atoms, the proportion of water in the mixture of water and aliphatic alcohol being from about 20% to 80% by weight, the said solution of mercapto carboxylic acid having been neutralized with one equivalent of an alkali metal hydroxide for each equivalent of mercapto and carboxyl groups in the mercapto carboxylic acid, the said mercapto carboxylic acid having the structure HS-Q-COOH where Q is a divalent organic radical selected from the group consisting of (1) an alkylene radical having the structure --C H where n is an integer from 1 to 4 inclusive, and (2) a carboxyalkylene radical having the structure C H (COOH)- where n is as already defined, the concentration of the mercapto carboxylic acid in the solution being about from 3% to 20% by weight, the temperature of said solution being about from 50 C. to 110 C. and the duration of said immersion being about from 0.5 to 2.5 hours,

(f) washing the thus-reacted textile to remove excess mercapto carboxylic acid and alkali metal hydroxide, and

(g) drying the washed textile.

7. The process of claim 6 wherein the mercapto carboxylic acid is thioglycolic acid.

8. The process of claim 6 wherein the mercapto carboxylic acid is 3-mercaptopropionic acid.

9. The process of claim 6 wherein the mercapto carboxylic acid is 4-mercaptobutyric acid.

10. The process of claim 6 wherein the mercapto carboxylic acid is 2-mercaptosuccinic acid.

11. A process for preparing a fibrous, cross-linked (carboxyarylthio) chlorodeoxycellulose in textile form, comprising:

(a) impregnating a fibrous cellulose textile with an aqueous 16% to 30% sodium hydroxide solution to obtain a swollen fiber structure,

(b) removing the sodium hydroxide by water-washing and solvent-exchanging with a water-miscible, cellulose-inert solvent, followed by exchanging with an inert aprotic solvent,

(c) reacting the resulting swollen fibrous cellulose with 2% to 20% thionyl chloride in dirnethylformamide solution, for about from 30 minutes to 24 hours, at a temperature of about from 20 C. to 30 C.,

(d) washing the reacted fibrous cellulose with dimethylformamide, ice water, and an aqueous 1% to 4% ammonia solution at room temperature to remove sulfur-containing byproducts and obtain a fibrous chlorodeoxycellulose in textile form containing about from 0.6% to 7.5% chlorine,

(e) immersing and reacting the immersed chlorodeoxycellulose textile in a solution of a mercapto carboxylic acid in a mixture of water and a straight-chain aliphatic alcohol having from 1 to 4 carbon atoms, the proportion of water in the mixture of water and aliphatic alcohol being from about 20% to by weight, the said solution of mercapto carboxylic acid having been neutralized with one equivalent of an alkali metal hydroxide for each equivalent of mercapto and carboxyl groups in the mercapto carboxylic acid, the said mercapto carboxylic acid being a mercaptobenzoic acid having the structure HSQCOOH where Q is a phenylene radical of the structure the concentration of the mercaptobenzoic acid in the solution being about from 3% to 20% by weight, the temperature of said solution being about from 50 C. to 110 C. and the duration of said immersion being about from 0.5 to 2.5 hours,

(f) washing the thus-reacted textile to remove excess mercapto carboxylic acid and alkali metal hydroxide, and

(g) drying the washed textile.

12. The process of claim 11 wherein the mercaptobenzoic acid is o-mercaptobenzoic acid.

13. A textile material consisting of a fibrous cellulose derivative having the structure (1100c Q, s zolmb where Z represents a segment of a crosslinked cellulose chain containing anhydroglucose units, In has a value in the range of about from 3 to 35, b has a value in the range of about from 1 to 26 but does not exceed 0.8 m, and 0 represents a divalent organic radical selected from the group consisting of (a) an alkylene radical having the structure C,,H where n is an integer from 1 to 4 inclusive, (b) a carboxyalkylene radical having the structure --C H- (COOH)- Where n is as already defined, and (c) a phenylene radical having the structure the aforesaid crosslinks in Z having the structure the number of these crosslinks being sufiicient to impart at least partial insolubility of the fibrous material in aqueous 0.5 molar cupriethylenediamine but insutficient to prevent swelling of the fibrous material in the cupriethylenediamine.

14. The cellulose derivative of claim 13 where Q is the alkylene radical.

15. The cellulose derivative of claim 14 wherein the alkylene radical is the methylene radical, -CH

16. The cellulose derivative of claim 14 wherein the alkylene radical is the ethylene radical, CH CH 3 14 17. The cellulose derivative of claim 14 wherein the al- References Cited kylene radical is the propylene radical, -CH CH CI-I Chem Abs 59, 660411 (1963) 18. The cellul se derivative of Claim 13 W11ere Q is the Schwenker et al.: Textile Research Journal, 33, 107-117 carboxyalkylene radical. (1963).

19. The cellulose derivative of claim 18 wherein the 5 carboxyalkylene radical is the carboxyethylene radical, GEQRGE LESMES, Primary 'EXammel --CH -*CH(COOH)--. J. CANNON, Assistant Examiner 20. The cellulose derivative of claim 13 where Q is the phenylene radical.

10 21. The cellulose derivative of claim 20 wherein the 8--31, 100, 168, 116.2; 117-138.5; 260-21 R, 212, phenylene radical is the o-phenylene radical. 231 232, DIG 4, DIG 6, DIG 21; 424-27 

